If you dress head to hoof in cow attire -- you'll be rewarded with an entree, a side item, and a drink.

Last year, nearly 800,000 people dressed up for free food. The chain expects nearly one million cow-clad guests for this year's event.

Chick-fil-A has a web site dedicated to the event. The site offers in-depth details on the celebration, cow costume ideas, as well as downloadable cow spots, masks and other bovine-themed accessories customers can use to create costumes.